“This alarming emergency compels us to take immediate action – to hold the federal government accountable to its obligation to clean up the largest nuclear waste site in the country,” said Washington Department of Ecology Director Maia Bellon.

Ecology is requiring the federal Department of Energy, through an enforcement order, to immediately assess the integrity of the tunnels and take swift corrective action.

“Our top priority is to ensure the safety of Hanford workers and the community. The collapse of this tunnel raises serious questions about how it happened and what can be done to make sure it doesn’t happen again. This enforcement order is necessary to make sure we get greater assurance about the condition of these tunnels and the Department of Energy’s plan to contain any further risks,” said Washington Gov. Jay Inslee.

“The infrastructure built to temporarily store radioactive waste is now more than a half-century old. The tunnel collapse is direct evidence that it’s failing. It’s the latest in a series of alarms that the safety and health of Hanford workers and our citizens are at risk,” said Bellon.

The enforcement order requires the U.S. Department of Energy to determine the cause of the tunnel collapse; assess the risk of further collapses; ensure the radioactive and chemical waste in the tunnels is stored safely; and submit a plan for permanently cleaning up waste in the tunnels.